NEET-XII-Physics
31: Capacitors
- #2The plates of a parallel-plate capacitor are made of circular discs of radii 5⋅0 cm each. If the separation between the plates is 1⋅0 mm, what is the capacitance?Ans : The capacitance of a parallel-plate capacitor is given by
`` C=\frac{{\in }_{0}A}{d}``
Here,
A = Area of the plate
d = Distance between the parallel plates
Given:
`` \,\mathrm{\,A\,}=\,\mathrm{\,\pi \,}{r}^{2}=\,\mathrm{\,\pi \,}\times {\left(5\times {10}^{-2}\right)}^{2}``
`` d=1.0\times {10}^{-3}\,\mathrm{\,m\,}``
`` {\in }_{0}=8.85\times {10}^{-12}\,\mathrm{\,F\,}/\,\mathrm{\,m\,}``
`` \therefore C=\frac{{\in }_{0}A}{d}``
`` =\frac{8.85\times {10}^{-12}\times 3.14\times 25\times {10}^{-4}}{{10}^{-3}}``
`` =6.95\times {10}^{-5}\,\mathrm{\,\mu F\,}``
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